When a wave travels through a medium, particles of the medium oscillate about their mean position. The number of oscillations per second is known as the frequency of the wave. SI unit of frequency is Hertz(Hz).
The distance between two consecutive crests or troughs is called wavelength of the wave. SI unit of wavelength is meter (m). It is denoted by symbol 'λ'.
When a wave travels through a medium, it creates a disturbance in the particles of the medium. As the disturbance moves along the direction of the wave, we say the wave is moving. The distance covered by that disturbance in one second is known as the velocity of the wave. It is given by the product of the wavelength and frequency of the wave.
Wavelength, frequency, and velocity of any wave are related according to the following relation,